Hello all, my dad owns a 2013 Silverado 5.3 lc9 with AFM DOD, it has 165k miles and running strong. This truck is a mostly highway truck with some city miles and lives in Illinois 8 months out of the year and north Texas area the rest of the year. It has had a steady diet of 5w30 Quaker state with ac delco oil filters. I’m wanting to switch the truck to a European oil of some sort, I’m thinking a 5w or 0w40 a3/b4, or castrol 5w30 a3/b4 euro. Two questions, is it okay to run a 5w40 euro oil in this truck? It has high miles and has some slight knocking on the bottom end not a huge deal, not looking to “cover it up” but it’s a worn in engine. The next question is if 40wt is okay in this AFM engine, is a non dexos rated euro oil okay? I’m under the impression that a euro oil a3/b4 mb229.5 rated oil is most likely higher “quality” than an oil that just meets the dexos rating. But I just want to make sure it’s not a huge deal. Thanks